1. Field of the Invention
The present invention relates to a mobile communication terminal and method for managing voice messages, and more particularly to a mobile communication terminal and a method for converting a voice message into a text message and storing the converted text message in a memory having a limited capacity without erasing a previously stored voice message.
2. Description of the Related Art
At present, one of the most frequently used application services of mobile communication terminals is a Short Message Service (SMS). At the current stage of development of the mobile communication technology, users of the terminals can exchange messages including voice data, image data and text only data. Users of terminals that utilize an All-IP (Internet Protocol) network can transmit data without a complicated conversion process, are always connected to the Internet with their unique IP addresses, and can engage in a one-on-one exchange of all kinds of messages. Such users can confirm received messages promptly without connecting to a server. A Push-To-Talk (PTT) service is an example of such service in the All-IP network. Namely, the PTT is a service wherein a user of one terminal can transmit a voice message, an image and a file to a user of another terminal connected to the Internet, without dialing.
As such, the characteristics of the All-IP network are designed to allow the terminal users to exchange multi-media messages, including voice and image data, as well as text data with one another without having to depend on a central server. Therefore the message size can be increased hundreds to tens of hundreds of times, compared with that of conventional text messaging.
Meanwhile, a general mobile communication terminal has inherent hardware restrictions, and therefore cannot secure a relatively large memory size to receive a plurality of multi-media messages. Therefore, a user of the general mobile communication terminal must always monitor whether the amount of received messages approaches a capacity limit of a message area allocated in its memory, and must manage the message area for receiving further messages.
In conventional voice message services, if a caller of one mobile communication terminal records his/her voice therein and then uploads it to a server, the server informs a corresponding recipient of another mobile communication terminal of arrival of a multi-media message corresponding to the caller's voice via SMS. Then the corresponding recipient connects to the server using his/her mobile communication terminal to receive the voice message.
A comparison of voice messages with text messages, and the inherent characteristics of voice messages, indicates that the data size per voice message is relatively larger than for text messages. For example, if the word “HELLO” is recorded as a voice message, even though voice data size depends on a reading speed and various environmental factors, the voice data will consume tens of kilobytes in a memory. However, if the same word is converted to a text message, then text data of the text message consumes a relatively small amount of the memory, compared with the voice data. More specifically, if the word “HELLO” is converted to a text message, text data of the text message consumes five bytes in the memory, because a character requires one byte. Therefore, when expressing the same information, the voice and text data differ greatly in terms of memory consumption.
Meanwhile, when a conventional mobile communication terminal receives a voice message, the voice message remains in a voice message area of a memory before a user directly confirms and then erases the voice message. From characteristics of the mobile communication terminal, since its memory size is restricted, if a voice message not confirmed by the user or a voice message confirmed but not erased by the user is successively stored in the memory, the size of the memory can be insufficient to store a newly received voice message.
A conventional technique for managing terminal memory to resolve such memory shortage, for mobile communication terminals that mainly provide SMS, is to inform a user that messages stored in a memory of the prior art mobile communication terminal must be erased when a total size of the messages exceeds a predetermined portion of the memory. Therefore, a user of the terminal directly selects and deletes corresponding messages.
U.S. Pat. No. 6,526,128 to Bahram G. Kermani entitled “PARTIAL VOICE MESSAGE DELETION” proposed that if the amount of messages stored in a memory of an automatic answering machine exceeds a predetermined portion, the stored messages are automatically erased from the memory, such that the memory can always receive a new message. However, such conventional automatic erasing method has disadvantages of a message to be deleted must be reconfirmed or a message not confirmed by the user may be automatically erased. Also, even if the “automatic deletion” mode is not set, when attempting to erase corresponding messages, the user must provide a confirmation of deletion one by one.
In a voice-text conversion technique, if a caller of one mobile communication terminal uploads his/her voice to a server, the server converts the voice to a text message and then transmits the converted text message to a corresponding recipient of another mobile communication terminal.
Korean Patent Application No. 10-2003-0045440, filed on Jul. 4, 2003, entitled “TERMINAL HAVING FUNCTION OF INTERCONVERTING BETWEEN VOICE MESSAGE AND TEXT MESSAGE AND METHOD FOR INTERCONVERTING BETWEEN VOICE MESSAGE AND TEXT MESSAGE IN THE SAME” discloses a technique for converting between a voice message and a text message. However, an object of the system described in that application is to provide a terminal for converting a voice message or text message received in a terminal to a format desired by a recipient of the terminal and outputting the same. Namely, if the terminal receives a voice message, the voice message can be converted to a text message and then outputted, or if the terminal receives a text message, the text message can be converted to a voice message and then outputted as voice. Therefore, the terminal can be easily used by the disabled.